Apparatus for producing non-woven fabric

ABSTRACT

An apparatus for applying weft yarns in a cross direction to warp yarns having an adhesive scrim thereon includes the warp yarns on a beam which are fed downstream of the apparatus by first laying the warp yarns onto a transfer belt to reduce the tension in the yarns. The warp yarns are fed upstream from a spool along a rotating tube on which they are mounted and pass through a tensioning apparatus to unify the tension in the various yarns running along the tube. The uniformly tensioned weft yarns pass through individual nozzles around the circumference of the rotating tube where the yarns are deposited onto the adhesive scrim. After the weft yarns are deposited on the warp yarns, the transfer belt moves the fabric having warp and weft yarns across a cooling section of a mandrel where the adhesive is set.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/403,303, filed 13 Apr. 2006, now U.S. Pat. No. 7,468,113, which is adivisional of U.S. application Ser. No. 10/621,084, filed 15 Jul. 2003,now U.S. Pat. No. 7,056,403, which is a continuation-in-part of U.S.application Ser. No. 09/869,941, filed 4 Jan. 2002, now abandoned, whichapplication is the Section 371(c) filing of PCT Internationalapplication No. PCT/US00/00571, filed 10 Jan. 2000. PCT Internationalapplication No. PCT/US00/00571 claims domestic priority from thefollowing U.S. provisional applications, U.S. application No.60/115,600, filed 12 Jan. 1999; U.S. application No. 60/154,717, filed20 Sep. 1999; U.S. application No. 60/155,364, filed 20 Sep. 1999, andU.S. application No. 60/155,365, filed 20 Sep. 1999. Each of theabove-referenced applications is hereby incorporated by reference asthough fully set forth herein, in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to textile fabrication apparatus, andmore specifically to an apparatus for aligning and depositingweft-orientated textile yarns, threads or filaments onto aligned warptextile yarns or filaments to produce non-woven fabrics having theappearance of woven fabrics.

2. Description of Background Art

Traditionally, fabrics having generally perpendicularly extending warpand weft yarns have been woven with a loom so that the yarns extendingin one direction pass over and under the yarns extending in theperpendicular direction. The yarn densities in both the warp and weftdirections, however, are limited not only by the diameters of the yarnsextending in the respective warp or weft directions but by the sizes ofthe orthogonally-extending yarns over and under which they are woven.Because woven yarns are typically comprised of yarns that extend inparallel and orthogonal directions in regular patterns, these fabricsare generally aesthetically pleasing especially when compared totraditional non-woven fabrics. The weaving of woven fabrics, however, isa relatively time consuming process having maximum production rates ofaround 10 ft/minute or less making woven fabrics expensive when comparedto nonwoven fabrics.

Traditional nonwoven fabrics comprise non-aligned, generally randomlyorientated yarns that are bound into a fabric mat. These types offabrics can be produced at extremely high rates of speed up to an orderof magnitude greater than woven fabrics. Further, depending on theadhesives used to join the yarns together, traditional non-woven fabricscan have physical properties equal to or in excess of woven fabrics ofcomparable thicknesses and densities. In variations of the traditionalnon woven mat fabrics a certain portion of the yarns may be aligned inone or more directions to create fabrics with anisotropic properties.Traditional nonwoven fabrics are generally not particularlyaesthetically pleasing and as such are not used very often inapplications where appearance is important.

Nonwoven fabrics that comprise a layer of aligned weft yarns and a layerof aligned warp yarns are also known that resemble woven fabrics. Thewarp and weft yarns of either layer do not intermingle, rather, analigned planer layer of warp yarns overlies an aligned layer of weftyarns, wherein the two layers are typically joined together by amechanical, thermal or chemical means, such as adhesive bonding. Becausethe layers do not intermingle, each yarn is uncrimped as it passes overor under other yarns. The result is a fabric with superior physicalcharacteristic when compared to woven fabrics depending on the manner inwhich the warp and weft layers are joined together. Further, because theyarns do not pass over and under one another, very high potential fiberdensities are potentially possible in both the weft and warp directions.Another advantage of nonwoven fabrics is that they have the potential tobe produced faster and cheaper than comparable woven fabrics.

As known in the prior art, a nonwoven fabric having the appearance of awoven fabric can be formed by pulling a sheet of aligned warp yarns overa cylindrical form as weft yarns are wound around the warp yarns.Typically, there is an adhesive on the warp fibers that bind the twolayers together. The resulting tubular cloth is then cut in the warpdirection and wound onto a take-up roll. For a variety of reasons,however, the prior art machines have not been able to deliver inproducing low cost woven-appearing nonwoven fabrics that also have highdensity yarn counts.

Several of the prior art apparatus for producing woven-appearingnonwoven fabrics were designed to produce fabrics comprised ofreinforcing fibers such as fiberglass and were not intended to producehigh density woven fabric replacements. U.S. Pat. No. 2,797,728 ofSlayer et. al. and U.S. Pat. No. 4,265,691 of Usui each describe anapparatus for making a fiberglass nonwoven fabric for use as areinforcement for subsequently produced composite materials. Thedescribed apparatus are not configured or designed to permit the rapidproduction of fabrics with tightly compacted warp and weft layers.

PCT publication WO 80/02850 describes an apparatus for producingnonwoven fabric, however, the manner in which the weft yarns aredeposited upon the warp yarns is not amenable to the rapid production offabrics having a dense weft layer. It can be appreciated that even smalllateral movement of a weft yarn as it is deposited onto the warp yarnswill cause the weft yarn to overlap an adjacent weft yarn, aconfiguration that is generally unacceptable in a finished high densitynonwoven fabric that is intended to resemble and substitute for a densetraditionally woven fabric.

It is to overcome the shortcoming in prior art apparatus that theapparatus of the present invention has been developed.

BRIEF SUMMARY OF THE INVENTION

The apparatus of the present invention takes a beam or roll of alignedside-by-side warp yarns and presents the side-by-side yarns as asubstantially flat sheet to a folding section where the sheet is urgedinto a cylindrical or tubular form so as to longitudinally follow thecylindrical outer surface of a mandrel. While in the cylindricalconfiguration, the warped yarns are fed through a weft yarn applicationsection of the apparatus where a plurality of longitudinally spacedspool stations are provided with each station containing a plurality ofcircumferentially spaced supply spools of weft yarn. The yarn from eachspool is fed upstream through a tensioning apparatus so that each yarncan be fed through an associated nozzle onto a laydown ring andsubsequently onto the outer surface of the warp yarns. The warp yarnsare held in adjacent relationship by an outer layer of a thermoplasticadhesive scrim and the thermoplastic adhesive scrim is heatedimmediately prior to receiving the weft yarns so the adhesive binds theweft yarns to the warp yarns as the weft yarns are laid substantiallyperpendicularly across the warp yarns. As the resultant fabric havingwarp and weft yarns progresses downstream of the apparatus, it passesthrough a cooling section where the adhesive is set to positivelyposition the weft yarns in overlying relationship on the warp yarns.

Once leaving the weft yarn application station, the now cylindrical andtubular fabric sleeve is fed through a cutting and unfolding sectionwhere the sleeve is cut longitudinally and unfolded from its cylindricalconfiguration into a flat continuous sheet of fabric which is ultimatelywound onto a roller at the downstream end of the apparatus.

The supply role of warp yarns can be assembled in a Beam WindingApparatus of the type described in U.S. Pat. No. 7,017,244 and U.S. Pat.No. 7,234,212, which is of common ownership with the present applicationthe disclosure of which is hereby incorporated by reference. Theadhesive scrim is applied to the warp yarns in any known manner.

After the fabric has been formed in the apparatus of the presentinvention, it can be passed through a laminator where a thin sheet ofbackup material can be adhesively bonded thereto for integrity and easeof handling.

Other aspects, features and details of the present invention can be morecompletely understood by reference to the following detailed descriptionof a preferred embodiment, taken in conjunction with the drawings andfrom the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is flow chart illustrating the various processes pertaining tothe fabrication of woven-like nonwoven fabric.

FIG. 2 is an isometric view of the textile fabrication apparatusaccording to one embodiment of the present invention.

FIGS. 3A and 3B are side views of the fabrication apparatus according toone embodiment of the present invention.

FIGS. 4A and 4B is a cross sectional view taken along line 4-4 of FIG. 2illustrating the path of the yarn sheet and the transfer belt.

FIG. 5 is a top view of the supply and folding sections with the warpyarn sheet disposed thereon as taken along line 5-5 of FIG. 4B.

FIG. 6 is a top view of the supply and folding sections of thefabrication apparatus with the transfer belt removed taken along line5-5 of FIG. 4B.

FIG. 7 is a top view of the cutting and folding section and the take-upsection of the fabrication apparatus.

FIG. 8 is a cross section taken along line 8-8 of FIG. 7.

FIG. 9 is a side view of the weft yarn application section.

FIG. 10 is an isometric view of the rotating tubular assembly.

FIG. 11 is a cross sectional view of the rotating tubular assembly takenalong line 11-11 of FIG. 9.

FIG. 12 is a cross sectional view a portion of the tubular assemblytaken along line 13-13 of FIG. 11.

FIG. 13 is a cross sectional view a portion of the tubular assemblytaken along line 13-13 of FIG. 11.

FIG. 14 is a side view of the cylindrical mandrel.

FIG. 15 is a cross sectional view of the interior of the cylindricalmandrel taken along line 15-15 of FIG. 14.

FIG. 16 is a partial cross sectional view of the weft yarn applicationsection taken along line 16-16 of FIG. 9.

FIG. 17 is a cross sectional view of the folding section taken alongline 17-17 of FIG. 5.

FIG. 18 is a cross sectional view of the folding section taken alongline 18-18 of FIG. 5.

FIG. 19 is a partial isometric view of the fabrication apparatusillustrating the laydown ring assembly.

FIG. 20 is an isometric view of the laydown ring assembly.

FIG. 21 is a cross sectional view of the laydown ring as viewed alongline 21-21 of FIG. 19.

FIG. 22 is a similar view as FIG. 21 with the weft and warp yarnsremoved and the ring in its retracted position.

FIG. 23 is an end view of the rotating tubular assembly illustrating theweft yarn nozzles.

FIG. 24 is a cross sectional view of the rotating tubular assembly takenalong line 24-24 of FIG. 16.

FIG. 25 is a cross sectional view of the rotating tubular assembly takenalong line 25-25 of FIG. 16.

FIG. 26 is a cross sectional view taken along line 26-26 of FIG. 23.

FIG. 27 is an enlarged cross sectional view taken along line 26-26 ofFIG. 23.

FIG. 28 is an enlarged cross sectional view taken along line 26-26 ofFIG. 23.

FIG. 29 is a partial cross sectional view of the rotating tubularassembly taken along line 29-29 of FIG. 25.

FIG. 30 is a partial cross sectional side view of the rotating tubularassembly illustrating a first alternative embodiment weft yarntensioning system.

FIG. 31 is an enlarged partial cross sectional view of a rotatingtubular assembly utilizing the first alternative embodiment weft yarntensioning system.

FIG. 32 is a partial cross sectional side view of another portion of therotating tubular assembly incorporating the first alternative embodimentweft yarn tensioning system.

FIG. 33 is a cross sectional view of the spring tensioner taken alongline 33-33 of FIG. 31.

DETAILED DESCRIPTION OF THE INVENTION Definitions

Beam: As used herein, a beam refers to any spool that is typically, butnot necessarily, cylindrically-shaped that may have end flanges on whicha plurality of aligned yarns have been wound.

Yarn: As used herein, a yarn is a continuous strand of one or morefibers or filaments made from any suitable organic or inorganic, naturalor synthetic material. Unless otherwise specifically indicated the term“yarn” is not limited to strands that are spun from a plurality offilaments.

Yarn Sheet: As used herein, a yarn sheet refers to the plurality ofplanar yarns aligned in the warp direction that form the warp layer inthe nonwoven cloth produced by the apparatus described herein.

Spool: As used herein, spool refers to any article adapted to hold aquantity of continuous yarn. Typically, yarn is wound onto a spool.

Environment for Apparatus of the Invention

As illustrated in FIG. 1, the apparatus of the present invention isprincipally concerned with applying weft yarns to a plurality of alignedside-by-side warp yarns in order to produce a non-woven fabric that hasthe appearance of a woven fabric. The apparatus utilizes a beam ofaligned warp yarns that is formed in a warper or beam winding apparatus,and wherein the warp yarns are subsequently coated with an adhesive tohold them in desired aligned relationship. It is the adhesive coatedwarp yarns that are utilized in the apparatus of the present inventionto form the non-woven fabric by wrapping weft yarns therearound in theweft yarn applicator of the present invention. Subsequent to theformation of the non-woven fabric, it can be passed through a laminatorwhere a thin sheet of material can be applied to one surface thereofprimarily for handling purposes.

The Apparatus Generally

The apparatus 40 and method of the present invention for applying andsecuring a layer of weft yarns to an underlying layer of warp yarns isshown generally in FIGS. 2, 3A, 3B, 4A and 4B. It will there be seenthat the apparatus includes a supply station 42, a folding station 44, aweft yarn application station 46, a cutting and unfolding station 48,and a take-up station 50.

In the supply station 42, a yarn sheet 52 comprised of aligned warpyarns with a thermoplastic adhesive scrim deposited on its top surfaceis unwound from a beam 54 at a controlled rate and pulled through thefabrication apparatus. The yarn sheet passes through the folding station44 where the flat yarn sheet is laid on top of a continuous, flexibleTeflon-coated transfer belt 56 and passed between a pair of folding bars58 that effectively wrap the yarn sheet and transfer belt around acentrally located elongated substantially cylindrical mandrel 60. Fromthe folding station, the wrapped yarn sheet passes through the weft yarnapplication station 46 where (i) a layer of weft yarn is applied to theouter surface of the yarn sheet by a high speed elongated rotatingtubular drum assembly 62 which includes a plurality of yarn spools 64carrying weft yarn 65, affixed to an outer drum that circumscribes thecylindrically shaped yarn sheet and supporting cylindrical mandrel, (ii)the yarn sheet is heated by hot oil contained within internal fluidchambers and passages in the core of the cylindrical mandrel 60 tosoften the thermoplastic adhesive scrim causing it to adhere to the weftyarns to be applied thereto, and (iii) downstream of the core's heatedsection, the resultant nonwoven fabric is cooled by water that is pumpedthrough other chambers and passages in the mandrel to resolidify thethermoplastic adhesive. From this section, the now tubular fabric passesinto the cutting and unfolding station 48 where the fabric is cutlongitudinally, i.e. in the warp direction prior to passing through apair of guide or refolding bars 66 that guide and reform the fabric intoa horizontally flat configuration. Finally, the resultant fabric 68 iswound onto a new beam or roller in the take-up station 50.

Each of the stations are described in greater detail below. It isappreciated that variations to the preferred embodiment of the apparatusare contemplated. For example, the supply station 42 could be replacedwith portions of a beam winder, such as of the type described in U.S.Patent Application No. 60/385,694 mentioned previously wherein aplurality of spools of yarn are provided to form the warp yarn sheet. Inthis type of configuration, an additional section would be provided toapply the thermoplastic adhesive to the warp yarns individually or theresulting warp yarn sheet. In other variations, a conventional laminatoris provided between the cutting and unfolding station and the take-upstation which applies pressure and heat to the nonwoven fabric tofurther compress and consolidate the fabric, thereby increasing thefabrics strength and other physical properties.

Motors 70, 72 and 74 are used to rotate the tubular drum assembly 62 onwhich the plurality of weft yarn spools 64 are mounted and these motorsare independent of motors utilized to drive the endless belt 56 used totransfer the associated yarn sheet 52 linearly through the weft yarnapplication station 46. Both sets of motors are controlled, however, bya computerized control system. Accordingly, an operator may vary factorsrelated to the properties and configuration of the resulting fabric 68such as by varying the rotational rate of the drum assembly versus thelinear speed at which the warp yarn sheet is fed through the apparatus.In this instance, the angle of the weft fibers relative to the warpfibers can be varied as well as the density (yarns per unit length) ofthe weft yarns.

The Supply Station

The supply station 42 is shown in FIGS. 2, 3B, 4B, 5 and 6. It generallycomprises (i) a substantially horizontally-disposed beam axle 76rotatably mounted to a framework 78, and (ii) a brake system 77 forvariably limiting the rotational speed of the axle on which the beam 54of yarn is mounted for unitary rotation.

In operation, the apparatus of the present invention produces fabric ata specified speed (typically from 20-40 ft/min). Accordingly, thealigned warp yarn sheet 52 must be unrolled from the beam 54 at the samerate. When the effective diameter (and circumference) of the yarn on thebeam is at its largest, such as when the beam is full, the necessaryrotational speed of the beam axle is relatively slow. However, as theeffective beam diameter decreases as the warp yarn sheet is unrolled,the rotational speed of the axle will have to increase correspondinglyto maintain the set sheet linear payout rate.

If a non-powered beam axle (i.e. no motor attached to it) is utilized inthe apparatus, the amount of force necessary to pull the yarn sheet 52off the beam 54 and overcome any rotational friction inherent in theaxle's coupling with the framework of the supply section would changewith the effective diameter of the beam. It is appreciated that thisforce translates into tension of the warp sheet as it is pulled throughthe apparatus and this tension would vary depending on the effectivediameter of the yarn sheet on the beam. It is desirable to produce afabric wherein the warp yarn sheet on the beam has a constant tensionduring the fabrication process and ideally the lowest possible tensionto assure the yarns are maintained in an aligned and substantiallystraight configuration. A motor and tensioning rollers to be describedlater, used to drive the endless transfer belt 56 that carries the warpsheet are driven at a predetermined speed. The brake system 77 isutilized to limit rotation of the beam while the warp sheet istransferred through the apparatus on the transfer belt so that aconstant low level tension is maintained in the warp sheet.

Folding Station

The folding station 44 is best illustrated in FIGS. 4B, 5, and 6, andincludes: (i) the framework 78; (ii) the front or upstream end of atransfer belt drive assembly 80; (iii) the front or upstream portion ofthe cylindrical mandrel 60; (iv) the folding bars 58 and (iv) variousrollers and associated hydraulic actuators 82 for guiding the warp yarnsheet to and along the transfer belt with the proper lateral alignment.

The transfer belt drive assembly 80, as is probably best seen in FIGS.4A and 4B, extends substantially the entire length of the apparatus withthe assembly including the flexible Teflon-coated transfer belt 56 whichextends around a drive roller 84 at the downstream end of the apparatuswith the drive roller being driven in a counterclockwise direction by amotor (not seen) in a housing 86. The transfer belt passes around andthrough tensioning and dancing rollers 88 to control its passage throughthe apparatus with the transfer belt having an upper run moving in adownstream direction from the supply roll end of the apparatus to thetake-up roll end of the apparatus. The transfer belt has a return runextending along a lower portion of the apparatus which, of course, movesin an upstream direction. At the upstream end of the transfer belt, ithas an incline run 90 where the belt moves in a downstream direction andupon which the warp sheet 52 is laid after it has passed through asuccession of tensioning and dancing rollers 92 so that a minimum oftension is present in the warp sheet as it is laid on the transfer beltand moved by the transfer belt through the apparatus. As the transferbelt with the warp sheet laid on top thereof approaches the downstreamend of the incline run 90, it engages the folding bars 58 which, aspossibly best seen in FIGS. 6 and 4B, are convergent in a downstreamdirection and sloped slightly downwardly in the downstream direction. Asthe transfer belt and warp sheet pass between the folding bars, they areurged into a cylindrical configuration as seen in FIG. 4B. The beltbecomes supported on the upstream end of the mandrel 60 which is also ofcylindrical configuration and the belt with the warp sheet thereon wrapssubstantially entirely around the mandrel with a small gap (not seen)along the bottom of the mandrel.

Once the warp yarn sheet and its Teflon coated fabric carrier belt havebeen wrapped around the front or upstream end of the cylindrical mandreland therefore are substantially cylindrically configured, they areadvanced into the weft yarn application station 46.

Weft Yarn Application Station

The weft yarn application station 46 is best shown in FIGS. 9-30 andcomprises: (i) the framework 78 that includes a protective enclosure 94;(ii) the cylindrical mandrel 60 (as partially described above); (iii) alaydown ring 96 on which the weft yarns are initially wound fordeposition onto the warp yarn sheet 52; and (iv) the rotating tubulardrum assembly 62 for winding weft yarns onto the laydown ring.

Referring first to FIG. 2, an isometric overview of the apparatus of thepresent invention is illustrated. The portion of the framework 78pertaining to the weft yarn application station 46 includes theenclosure 94 adapted to protect operators of the apparatus in case of afailure of the rotating tubular assembly or one of the items attachedthereto. It can be appreciated that if a part of the tubular assemblybreaks free during high speed rotation, the part would be propelledradially outwardly and could potentially injure an operator if notcontained. The protective enclosure is preferably fabricated fromreinforced steel and/or aluminum and includes a retractable door 100that permits the operators access to the spools 64 of weft yarn duringsetup. The retractable door could include, if desired, a plurality ofshatterproof windows (not shown) through which an operator can view theoperation of the rotating tubular drum assembly 62. The windows wouldtypically be fabricated from an impact resistant plastic, such aspolycarbonate, or a safety glass. Additionally, in the preferredembodiment the drive motors 70, 72 and 74 are mounted high on theframework with associated drive belts 102, 104 and 106, respectively,extending downwardly to couple with the rotating tubular assembly. Auser interface 108 including informational readouts and input devicesfor communicating with the programmable control system are alsopositioned on the framework 78.

Referring specifically to FIGS. 14 and 15, the cylindrical mandrel 60includes (i) a heated section 110 and (ii) a cooled section 112. Bothsections are generally similar, comprising a network of fluid chambersand passages that terminate in inlet ports and outlet ports. The fluidchambers and passages in the heated section 110 are separated from thosein the cooled section by a barrier wall 114 at the longitudinal centerof the mandrel. In the heated section of the mandrel, hot oil is pumpedinto an inlet port 116 located near the front end of the mandrel, fromwhich it flows down an inlet sleeve 118 that generally extends to thecenter of the mandrel adjacent to an outer metallic cylindrical wall 122of the mandrel where it then flows around a chamber 124 to an outletpassage 120 interiorly of the inlet sleeve 118. The heat from the hotoil is transferred through the wall 122 of the mandrel and the transfercarrier belt 56 to the warp yarn sheet 52 to soften and melt thethermoplastic adhesive scrim contained on the warp yarn sheet. From theoutlet passage, the oil is passed out of the mandrel through an outletport 128. Although not specifically illustrated, a hot oil reservoir andassociated heater are utilized to heat the hot oil to a suitabletemperature. A fluid pump (not shown) is provided to pump the oil fromthe reservoir and through the mandrel. In a preferred embodiment, tomelt a copolyester adhesive having a melting point of around 280 degreesF., the surface of the mandrel is maintained at around 325 degrees.

The cooled section 112 of the mandrel comprises fluid chambers andpassages generally similar to those utilized in the heated section.Chilled water is passed into an inlet port 130 located near the back ordownstream end of the mandrel, down an inlet sleeve 132 and through achamber 134 before entering an outlet passage 136 from which it flowsout of the mandrel through an outlet port 138. The water cools the outerwall of the mandrel above it along with the associated nonwoven fabricand carrier belt 56 to a temperature below the melting point of thethermoplastic adhesive thereby causing the adhesive to solidify andsecure the newly applied weft yarns to the warp sheet. Although notshown, a pump is provided to pump the chilled water through themandrel's cooling section. Additionally, a chilling station is utilizedto transfer heat from the water before recirculating it back into themandrel. The water may contain additives to prevent it from boiling andto minimize the corrosion of the metallic surfaces of the passages andchambers of the cooling section. In an alternative embodiment, watercould be pumped directly from a tap into the mandrel and directed down adrain upon exiting the cooling section through the outlet port.

As the warp yarn sheet 52 is being heated by the heated section 110 ofthe cylindrical mandrel 60, the yarn sheet is transferred on thetransfer belt 56 into a cylindrical space beneath the weft yarn laydownring 96 that encircles the mandrel, the carrier belt and the warp yarnsheet. The laydown ring is best illustrated in FIGS. 21 and 22 andincludes an inside cylindrical surface 140 spaced above the warp sheet52 by about 0.005-0.015″. It is to be appreciated that it is desirableto have the inside surface as close as possible to the outer surface ofthe warp yarn sheet without contacting the warp yarn. Practically,however, a small gap must be maintained to account for any localizedvariations in the thickness of the warp yarn sheet and the Teflon-coatedtransfer belt. The laydown ring also includes a frustoconical or slopedsurface 142 on which the weft yarns 65 are deposited by weft yarnnozzles 144 of the rotating tubular assembly 62 (described in detailbelow) before sliding therefrom in a downstream direction onto thesurface of the warp yarn sheet. The frustoconical surface tapersrearwardly or in a downstream direction and radially inwardly,terminating at an intersection with the inside cylindrical surface 140of the laydown ring.

The laydown ring's radial spacing is fixed relative to the mandrel 60.However, the ring is mounted to a linearly slidable frame 146 having ahydraulic actuator 148 that is mounted to the framework 78 of theapparatus to selectively move the frame and ring longitudinally in anupstream/downstream direction relative to the mandrel. Accordingly, whensetting up the apparatus, such as threading the weft yarn through theweft yarn nozzles 144 as will be explained in more detail later, thelaydown ring 96 can be moved upstream away from the weft yarn nozzles toa retracted position, permitting easier operator access. In the normaloperational downstream position, the frustoconical surface 142 of thering is positioned directly beneath the nozzle outlets with only a smallamount of spacing between them.

Operationally, weft yarns 65 from each nozzle 144 being utilized arelaid down and wrapped at least partially around the frustoconicalsurface 142 at the same longitudinal location, pushing the previouslylaid weft yarn down the frustoconical surface in a downstream direction.Eventually, the loops of weft yarn are pushed by subsequent loops offthe edge of the frustoconical surface and down onto the surface of thedownstream moving underlying warp sheet. The density of the weft yarnsis directly related to the linear speed at which the yarn sheet ismoving longitudinally downstream compared with the speed the weft yarnsare being wound onto and pushed off the edge of the laydown ring. Forinstance, to maximize the weft density of the fabricated fabric, thespeed of the belt must be equal to the speed that loops of weft yarn arewrapped around the ring times the diameter of the weft yarn. Any slowerspeed will result in an overlap of weft yarns. Faster carrier beltspeeds resulting in a greater linear speed of the warp sheet will resultin fabrics wherein the weft yarns are spaced from each other creatingfabrics with lower weft densities.

The laydown ring 96 offers several advantages over laying the yarnsdirectly onto the warp sheet itself from the yarn nozzles 144. First,because the yarns are laid onto the sloped surface 142 of the ring withthe ability to move down the slope, they can be placed closer togetherwithout the risk of overlap of two or more loops of yarn. For example,if a yarn from a subsequently located nozzle is laid on a previouslylaid yarn from an adjacent nozzle in a partially overlappingrelationship due to small but undesirable movements in the yarn duringthe high speed winding operation, the previously laid yarn is pusheddown the slope, making room for the subsequently-laid yarn to bepositioned flushly against the sloped frustoconical surface of the ring.In contrast, if a weft yarn were to be laid directly onto the surface ofthe warp sheet from a nozzle, it would be substantially fixed in placeby the softened thermoplastic adhesive and possibly out of position.Accordingly, if the next loop of weft yarn were to partially overlap apreviously laid loop, the previously laid loop would not slide forwardlyto permit the subsequent loop to lie flat against the sheet. Further, ifthere is sufficient thermoplastic adhesive on the warp sheet, theoverlapped subsequent loop of yarn may become fixed to the previouslylaid loop creating a defect in the resulting fabric. It is appreciatedthat the subsequently laid loop on the laydown ring will not moverearwardly, because of the loop being deposited on the yarn sheet behindit. Ultimately, the ring provides more precisely aligned and dependableweft layers for a given degree of variability within the fabricfabrication apparatus when compared to a similar apparatus wherein theyarns are laid directly onto the warp yarn sheet.

The use of the sloped surface 142 on the laydown ring also helpsminimize the amount of tension in the weft yarns 65 as they aredeposited on the warp yarn sheet 52. Low tension in the fabric in boththe warp and weft directions is important to help ensure the dimensionalintegrity of the resulting fabric. For instance, if the weft yarns arelaid down on the warp yarns under high tension, the weft yarns wouldcontract as the tension is released when, for example, the weft yarnsare cut to create a flat fabric sheet in the cuffing and unfoldingsection. This contraction could cause localized nonlinear deviations ofthe warp yarns that are visually unappealing. A certain amount oftension is necessary in the process of wrapping the weft yarns aroundthe warp sheet, although as described below, the tension is maintainedat the lowest possible levels because of the design of the rotatingtubular assembly as will become more apparent hereafter. However, sincethe weft yarn loops are laid on the laydown ring at a first diameter ofthe frustoconical sloped surface and slide onto the warp sheet which hasa smaller diameter, much of the tension in the loop is relieved as theloop slides down the sloped surface and onto the warp sheet. Althoughthe loops of weft yarn are still under some tension when they are pushedoff the ring onto the warp yarn sheet, the amount of tension is reducedsomewhat by friction between the frustoconical surface and the yarn suchthat the yarn loop relaxes somewhat as it moves from a larger diameterportion of the sloped surface to a lower diameter portion and ultimatelyonto the warp yarn sheet. It is to be appreciated, however, that theweft yarn is laid down onto the warp sheet under enough pressure toensure that the yarns are circumferentially straight.

As best shown in FIGS. 26 and 28, a resilient ring 150 made of anelastomeric material is placed within a recess in the mandrel 60directly below the laydown ring 96 (when the laydown ring is in itsdownstream operational position). The resilient ring 150 extendslongitudinally a little in front of the front side of the laydown ringand a little beyond the rear edge of the laydown ring. The surface ofthe resilient ring is substantially flush with the surface of the steelmandrel. In a preferred embodiment, the resilient material comprises asilicone rubber although any elastomeric material or sponge that cantolerate the elevated temperatures of the mandrel can be utilized. Asdescribed above, the typical spacing between the top surface of the warpsheet and the bottom surface of the laydown ring is 0.005″ to 0.015″. Adefect in the warp sheet, such as a knot or fold, or a defect in theTeflon-coated transfer belt 56, such as fold or crease, could cause thespacing to disappear in the location of the defect. When such a defectis present, the resilient material of the ring 150 compresses inwardlyso that the defect can pass therethrough without hindering the continuedoperation of the fabrication apparatus.

The rotating tubular assembly 62 is provided to simultaneously andrapidly wind a large number of spools of weft yarn 65 under controlledlevels of tension onto the laydown ring 96 for eventual deposition ontothe surface of the warp sheet 52 to form the nonwoven fabric. Therotating tubular assembly is illustrated in FIGS. 9-16, 19, and 21-29.The rotating tubular assembly comprises: (i) a rotating outer tubesubassembly 152; (ii) a rotating inner tube subassembly 154; (iii) anozzle head subassembly 156; and (iv) four motor and drive beltcombinations for rotating and controlling the speed of thesubassemblies.

A preferred embodiment of the rotating tubular assembly 62 is capable ofrotating at up to 600 RPM and laying down weft yarn 65 from up toforty-eight separate circumferentially and axially spaced spools 64simultaneously. Depending on the yarn configuration utilized, the fastrotational speed combined with the large number of spools permits highquality non-woven fabric to be produced at a rate of 20-40 feet aminute. This compares very favorably to weaving looms for woven fabricswhich are typically limited to production speed of no greater than 10feet per minute.

Referring primarily to FIGS. 2, 9, 10, 12, 13, 16, 21, and 22, the outertube subassembly 152 includes: (i) an elongated tube 158 rotatablymounted on the framework 78 via pairs of inner 160 and outer 162bearings positioned near each end of the tube; (ii) six longitudinallyor axially spaced weft yarn stations 164 with each station having eightspider arms 166 circumferentially spaced around the outer tube 158 withdistal ends adapted for holding spools 64 of weft yarn 65; (iii)longitudinally-aligned conduits 168 and associated inlet blocks 170 forfeeding the weft yarns from the yarn stations towards the front orupstream end of the outer tube assembly; (iv) upstream 172 anddownstream 174 belt drive rings for interfacing with drive belts; and(v) a nozzle head subassembly mounting ring 176 with a plurality ofpassages 178 therein through which the weft yarns can pass.

A total of forty-eight spools 64 of weft yarn 65 are attached to theexterior of the outer tube 158 of the outer tube subassembly 152 at thesix longitudinally spaced weft yarn stations 164 over an approximately12-foot length. Each station includes eight spider arms 166 that areequally circumferentially spaced around the exterior surface of theouter tube. The distal end of each of spider arm has a spindle 168adapted to receive a spool 64 of yarn. Each spindle extends forwardly orupstream and is slanted radially inwardly such that the face of anattached spool is angled toward the exterior of the outer tube 158. Thespindles each have outwardly biased lock fingers 170 that releasablysecure a yarn spool to it and prevent the spool from sliding off thespindle, especially when the rotating tubular assembly is stationary. Asthe assembly spins, potentially significant centrifugal loads aregenerated. The magnitude of centrifugal loads on a rotating bodyincrease for a given amount of rotating mass as that mass gets fartherfrom the axis of rotation. Ideally, the spools of yarn are located asclose to the axis of rotation as possible, however this consideration isoffset by (1) the desire to fit a large number of spools to the rotatingtubular assembly and (2) the desire to use larger spools of yarn (withgreater diameters) so that the apparatus can operate for longer periodsbetween spool replacement. In the illustrated preferred embodiment, thespider arms elevate the spools above the surface of the outer tube ashort distance but which is great enough to accommodate relatively largespools.

The spindles 168 on each spider arm 166 at each of the six stations arelocated the same distance from the outer tube's axis of rotation.Accordingly, approximately the same centrifugal force is acting on eachyarn of each spool at a given station as it is pulled off the spool andfed to a respective weft yarn nozzle at the front or upstream end of therotating tubular assembly. In contrast, if several layers of spools werestacked on top of each other, a greater centrifugal force would act uponthe outermost spools, thereby necessitating a greater force to pull theassociated yarn off the spool and feed it toward its nozzle 144 thananother spool located closer to the axis of rotation. Accordingly, thetension in the yarns 65 pulled from outer spools 64 would be greaterthan that from inner spools. It is to be appreciated that it isdesirable that all yarns deposited on the warp sheet 52 havesubstantially the same tension, otherwise visual defects in the fabriccould result when the weft yarns of the fabric are cut to form a flatsheet.

Referring to FIGS. 12, 13, and 16, the yarn 65 from each spool 64 ispassed through an associated inlet block 170 mounted to the top of theouter tube 158 and fed upstream toward the front or upstream end of theouter tube and its associated weft yarn nozzle 144 via a linear rigidlongitudinally-aligned conduit 168. The inlet block includes an inletopening 180 with a plastic (or ceramic) bushing 182 press fit therein tominimize the friction between the yarn and the sides of the block andprevent fraying. A passage 184 extends downwardly and forwardly from theinlet opening 180 until intersecting with a longitudinally alignedpassage 186 which matingly receives the end of the conduit 168 thereinat the upstream end of the block. The block's longitudinally alignedpassage 186 is open at the block's downstream end as well, and isadapted to receive a nozzle attached to a compressed air line (FIG. 12)to assist in threading or feeding of the yarn into the inlet opening 180and down the conduit 168 when the apparatus is initially set up andthreaded. To advance the yarn through the inlet block and conduit duringsetup, the nozzle with compressed air flowing through it is temporarilyplaced in the back end opening of the longitudinally-aligned passage186. The compressed air flowing through the passage creates a vacuum atthe inlet 180, which pulls the yarn therefrom to the intersection withthe longitudinally aligned passage. From there, the yarn is pushed bythe flow of compressed air down the conduit toward an associated nozzle.

In operation as the outer tube subassembly 152 is rotating at highspeed, the yarn 65 contained within the conduits 168 will be forcedradially outwardly against the outside of the conduit by centrifugalforce acting on the yarn. The contact between the inner conduit wall andthe yarn will increase the force necessary to pull the yarn from thespool to the associated nozzle, thereby increasing the effective levelof tension in the yarn. It will be appreciated that since yarns fromspools at the downstream end of the rotating outer tube 158 travel agreater distance in a conduit 168 than yarns from spools attached tomore upstream located stations, a higher amount of force will berequired to pull them through the conduit. The different lengths ofconduit will result in different levels of tension developed in theyarns. As discussed above, the tension in the yarns should be similarwhen laid down upon the laydown ring 96 and subsequently the warp sheet52 to ensure uniformity and visual appeal of the finished fabric.Accordingly, the inner tube subassembly 154 with a tension equalizationmechanism 188 is provided to help ensure that the tension in all of theweft yarns 65 is essentially equal as they are fed through the weft yarnnozzles 144 and around the laydown ring 96.

The inner tube subassembly 154, as probably best seen in FIG. 26 withsupporting information in FIGS. 4A and 9, is a cylindrical tube or innertubular member 190 that circumscribes the mandrel 60 and is supportedinteriorly of the outer tube subassembly 152 by the pair of inner ringbearings 160 which are disposed adjacent to opposite ends of therotating tubular assembly 62. The cylindrical tube 190 has a maincylindrical body 192 extending substantially the entire length of thecylindrical tube 190 with cylindrical axial extensions 194 at each endaffixed thereto for unitary rotation therewith. The inner races of thepair of inner ring bearings 160 are secured to the associated extensioncylinders 194 so that while the inner tube subassembly is operativelyconnected to the outer tube subassembly in radially spaced relationshiptherewith and in a manner such that they could pivot or rotate relativeto each other, in operation of the apparatus they actually rotate inunison.

The downstream end of the inner cylindrical tube 190 has a flange 196defining a axially crowned circumferential surface for receipt of adrive belt (FIGS. 4A and 9) which extends upwardly and wraps around thedrive shaft of a drive motor 74 which is provided to rotate the innertube subassembly at a preselected speed.

The inner tube subassembly 154 serves as a base for the tensioningmechanism 188 to encourage uniform tension in the weft yarns 65 as theyare laid onto the warp sheet 52 as illustrated in FIGS. 6-29. Thetensioning mechanism comprises (i) the afore-noted inner cylindricaltube 190 that is coupled with the outer tubular member 158 through theinner set of ring bearings 160; (ii) a rubber lined traction ring 198attached to the inner cylindrical tube proximate its upstream end; and(iii) the motor 74 and the belt 106 for controlling the rotation of theinner tubular member independently of the outer tubular member.

The inner tubular member 190 extends to the downstream end of the outertube 158 as best shown in FIG. 4A. As mentioned previously, thedownstream end of the inner tubular member is flanged at this locationand includes the longitudinally crowned circumferential surface 196adapted to frictionally receive the drive belt 106. The drive beltpasses around the drive shaft of the inner tube drive motor 74 that issecured to the framework 78 of the apparatus at the downstream end. Thedrive motor is electronically coupled to the control system for theapparatus to selectively and precisely control the rotational speed ofthe inner tubular member.

The outer tubular member 158 has a conduit termination ring 202 at itsupstream end as will be described in more detail hereafter with thetermination ring having an axially crowned circumferential surface 204adapted to receive the drive belt 104. The opposite or downstream end ofthe outer tubular member also has an axially crowned circumferentialsurface 208 for receipt of the corresponding drive belt 102 and themotors 70 and 72 respectively are mounted above the axially crownedcircumferential surfaces on the framework so that the drive beltsoperatively engaged with the drive shafts of the motors can extenddownwardly and engage the axially crowned circumferential surfaces torotatably drive in unison or individually the outer tubular member. Thetwo drive motors 70 and 72 are controlled by the control circuit for theapparatus so as to be driven in unison, or individually, at a speedproportional to the rotational speed of the inner tubular member 190.

The weft yarn 65 from each spool 64 exits its associated conduit 168within the upstream belt drive ring 172, extends through a passage 214in a circumferential block 216 that is secured to the belt drive ringfor rotation therewith, exits the block 216 through an outlet 218 with aplastic or ceramic bushing press fit therein and wraps around agenerally cylindrical rubber coated surface 220 of the traction ring ordrum 198 for a selectively variable distance that might approximate, byway of example, about 300 degrees before leaving the traction ring andpassing into the nozzle head assembly 176 (described in detail below)and ultimately out of an associated nozzle 144.

Operationally, the friction between the rubber of the traction ring 198and each yarn 65 as it is wrapped around the traction ring causes thetraction ring to grip and pull each yarn off its associated spool 64 andthrough its associated linear conduit 168. A portion of the upstreambelt drive ring 172 as illustrated in FIG. 26 is fixedly attached to theupstream end of the outer tube 158 and has passages 224 extendinglongitudinally through it associated with each weft yarn and inalignment with a passage 214. As can be seen in FIG. 29, the upstreamface or end 228 of the circumferential block 216 is stepped with eachstep being associated with an outlet 218 (FIG. 29). Each step islongitudinally displaced at least 0.020″ from an adjacent step in thepreferred embodiment providing a maximum longitudinal offset of 0.96″between the first and last outlets. Accordingly, each nozzle 144overhangs its own longitudinal location or step on the rubber linedportion of the traction ring 198 on which the associated yarn is laidwhen partially circumscribing the traction ring. This arrangement helpsminimize the possibility that the yarns will overlap significantly orbecome entangled with each other.

The total force applied by the inner tubular member 190 to pull all theyarns 65 off their spools 64 and through their associated conduits isequal to the sum of all individual force amounts necessary to pull eachyarn to the traction ring. It is to be appreciated that the forcenecessary to pull a yarn from a spool to the traction ring is equivalentto the tension level developed in the yarn multiplied by the area of theyarns cross section. As discussed above the yarns from the moredownstream stations 164 will require greater force to pull them to thetraction ring than yarns from stations located closer to the tractionring, but once passing upstream from the traction ring, the weft yarnswill be under substantially the same tension.

Once each yarn has been wrapped partially around the traction ring 198it is removed from the ring and passed into the nozzle assembly 156 andthrough its associated nozzle 144 prior to being laid onto and wrappedaround the laydown ring 96. The total force necessary to pull each andevery yarn off the traction ring when the inner tubular member isrotating at the same speed as the outer tube is the same as the totalforce necessary to pull every yarn off its respective spool and throughits respective conduit. However, the actual force applied to eachindividual yarn to pull it off the traction ring is equivalent to thetotal force divided by the total number of yarns. In other words, thetension level in each yarn as it is pulled through its nozzle and laidonto the laydown ring is substantially the same regardless of thelongitudinal position of the spool from which the yarn originated alongthe length of the outer tube.

As mentioned previously, it is desirable to control the tension in theweft yarns 65 as they pass through their associated nozzles 144, andthis is accomplished by slightly varying for a short period of time therotational speed of the outer tubular member 158 relative to therotational speed of the nozzle assembly 156 which affects the distancearound the traction ring that each yarn extends. As probably best seenin FIG. 26, the nozzles 144 are mounted in equal circumferentiallyspaced relationship on the mounting ring 176 which is secured to a ringbearing 232 that in turn is rotatably supported on an inset bearing 234seated in the circumferential block 216 described previously throughwhich the weft yarns extend prior to being wrapped on the traction ring.The ring bearing 232 has an axially crowned circumferential surface 236for receipt of still another drive belt 238 that is driven by the driveshaft of a motor 240 also mounted on the framework 78 vertically abovethe rotating tubular assembly. This motor is driven at the same speed asthe other three motors 70, 72 and 74 in operation of the apparatus butby slightly varying for a short length of time the speed of the motor240 relative to the speed of the motors driving the outer and innertubular members, the relative circumferential relationship of thenozzles to designated locations on the traction ring can be variedthereby varying the circumferential distance the yarns are engaged withthe traction ring and thus the tension in the yarns upstream from thetraction ring toward the yarn nozzles. Accordingly, the yarn tension canbe desirably selected by relative rotational speeds of the motorsdriving the nozzle ring and the outer tubular member until a desiredtension is obtained in the yarns upstream from the traction ring and atthat point synchronizing the rotational speeds of the nozzle ring andthe outer tubular member to maintain the desired tension.

As mentioned previously, prior to laying the weft yarns 65 onto the warpsheet 52 from the laydown ring 96, the transfer belt 56 and warp sheethave moved along the upstream end of the mandrel 60 where they have beenheated to a temperature sufficient to soften the adhesive scrim on thewarp sheet. Accordingly, as the weft yarns are laid onto the adhesivescrim on the outer surface of the warp sheet, they remain in positionand as the transfer belt moves the warp and weft yarns along themandrel, they ride over the cooling section 112 of the mandrel where theadhesive sets to positively secure the weft yarns to the warp sheet atthe locations where the weft yarns were laid onto the warp sheet.

Cutting and Unfolding Station

As the transfer belt 56 moves the warp and weft yarns out of the weftyarn application station, they pass a cutting wheel 242 (FIG. 4A)positioned immediately beneath the mandrel 60 and along its longitudinalcenterline so the cutting wheel which is driven by a motor (not seen)can cut the weft yarns 65 along the gap between the lateral edges of thetransfer belt along the bottom of the mandrel. The cutting of the weftyarns releases the warp and weft yarn fabric 68 so it can be unfoldedfrom its cylindrical configuration and converted to a flat orientationby the unfolding bars 66.

There are a pair of unfolding bars 66 which are tubular in configurationand rotatably driven about their longitudinal axes. The bars convergeand slope upwardly in a downstream direction so that as the transferbelt 56 engages the rotating bars, it is encouraged to unfold from itsgenerally cylindrical configuration to a flat orientation. The foldingbars are rotated in opposite directions so that as the bars engage theside edges of the transfer belt, they force the side edges outwardly andupwardly until the belt assumes a flat orientation and at that point inthe process the belt crosses over a large idler drum 244 (FIG. 4A) nearthe downstream end of the apparatus.

After passing over the large idler drum 244, the transfer belt 56 withthe fabric 68 on its top surface and in a flat orientation moves down aslight decline run 246 of the transfer belt prior to the belt passingaround the drive roller 84 where the fabric is separated from thetransfer belt and pulled upwardly around a plurality of idler andtensioning rollers 248 before being wound onto a driven take-up rolleror beam 250. The take-up roller is driven at a speed consistent with thespeed of the transfer belt so as to not place undue tension in thefabric.

Operation

In operation of the apparatus, the beam 54 of aligned warped yarnshaving an upper layer of a thermoplastic adhesive scrim is mounted on anaxle having a break to selectively resist removal of the warp yarn fromthe beam. The warp yarns 52 are passed around the plurality of idler andtensioning rollers before being laid upon the top surface of thetransfer belt 56 which carries the warp yarns through the weft yarnapplication station 46. However, before the weft yarns are applied tothe warp yarns, the belt with the warp yarns thereon is folded into acylindrical configuration and moved into surrounding relationship withthe longitudinally extending generally cylindrical mandrel 60 having aninternal heating section 110 at its upstream end and an internal coolingsection 112 at its downstream end. As the belt and warp yarns pass overthe heating section, the temperature of the thermoplastic adhesive scrimis elevated until the adhesive becomes tacky and in this condition, thewarp yarns are fed into the weft yarn application station.

In the weft yarn application station 46, the plurality ofcircumferentially spaced spools 64 of weft yarn 65 provided atlongitudinally spaced locations are rotated with yarns from each spoolmoving in the confined conduits 168 in an upstream direction where theypass through the tensioning system 188 prior to passing through theindividual circumferentially spaced nozzles 144 which lay the yarns ontothe stationary laydown ring 96 that circumscribes the warp yarns inclose relationship therewith.

The laydown ring has the frustoconical surface 142 that tapers inwardlyin a downstream direction so that the yarns deposited thereon are urgedin a downstream direction and are pulled off the downstream edge of thefrustoconical surface onto the warp yarns moving linearly therebeneath.The weft yarns adhere to the tacky adhesive scrim as they are laid inposition in a substantially perpendicular relationship with the warpyarns.

The fabric 68 of warp yarns with overlying weft yarns moves linearlyalong the weft yarn application station and across the cooling section112 of the mandrel where the temperature is dropped to cure theadhesive, thereby positively holding the weft yarns in position on thewarp yarns.

It is to be appreciated that the fabric 68 of warp and weft yarns is ina cylindrical configuration as it leaves the weft yarn applicationstation and immediately passes over the rotary cutting wheel 242 whichcuts the weft yarns along the bottom edge of the cylindrical fabricalong the gap between the lateral edges of the transfer belt.

After the fabric has been cut by the cutting wheel, it is encouraged tounfold from its cylindrical form into a flat elongated sheet by the pairof rotating unfolding rods, and as soon as the fabric and transfer belthave been flattened out, they pass over the idler drum 244 and aslightly further distance downstream where the transfer belt returns inan upstream direction, the fabric is separated therefrom and passes overthe plurality of idler and tensioning rollers before being wound ontothe take up drum or beam 250.

ALTERNATE EMBODIMENT

An alternative embodiment of a tensioning system is shown in FIGS.30-33. FIG. 30 is a fragmentary section looking at the upstream end of arotating tubular member 252 which is similar in many ways to thepreviously described embodiment. In other words, there are a pluralityof stations of spools 64 with the spools on the rotating tubular memberwith only one station being seen. The spools as in the previouslydescribed embodiment have weft yarn 65 which is fed upstream through aconduit system 168 as previously described so that the yarns ultimatelypass through one of a plurality of equally circumferentially spacednozzles 144 from which the yarns are deposited onto the laydown ring 96and from there onto the warp yarns 52 carried along the mandrel 60 bythe transfer belt 56. In this embodiment, however, there are not innerand outer rotating tubular members as in the prior embodiment, butrather only one rotating tube 252 that is rotatably driven by a belt 254passing around a conduit termination ring 256 which forms part of therotating tube at its upstream end and is rotatably supported within theframework 78 of the apparatus by a pair of ring bearings 258 (only onebeing seen). Passages 260 through the termination ring 256 are alignedwith associated passages 262 through a circumferential block 264, andagain, the nozzle assembly 176 is rotatably mounted on thecircumferential block 264 identically to the previously describedembodiment. The nozzle assembly is rotatably driven again by the motor240 even though the speeds of the motors 70 and 72 are synchronized sothat they rotate at identical speeds.

The tension in the yarn 65 in this embodiment is controlled byconventional adjustable tensioners 266 which are secured to the yarninlet blocks 170 associated with each spool of weft yarn. A bracket 268having a plate 270 with an eyelet 272 therethrough is secured to eachinlet block so that yarn emanating from the associated spool 64 passesthrough the eyelet, the tensioner and subsequently into the inlet blockfrom which it passes upstream to an associated nozzle 144.

The tensioner 266 itself is a conventional thread or yarn tensionerwhich is best seen in FIG. 33 to have an upstanding threaded rod 274, alower fixed ring plate 276, an upper adjustable ring plate 278, a capscrew 280 threaded onto the rod, and a coil spring 282 disposed betweenthe cap screw and the adjustable ring plate. The threaded rod passesthrough the bracket 268 so that a nut 284 can secure the tensioner tothe bracket in the position illustrated best in FIG. 31.

In using the tensioner, a weft yarn emanating from a spool 64 andpassing through the eyelet 272 in the plate 270 is threaded between thefixed and adjustable ring plates before being inserted into the inletblock 170. The tension in the yarn is adjusted by moving the cap screw280 up or down the threaded rod thereby affecting the pressure by whichthe adjustable ring plate 278 is compressed against the fixed plate 276and thereby yieldingly resisting movement of the yarn 65 which passesslidably therebetween. The tension in the yarn passing through thetensioner is manually set such that the tension in each of the yarnsemanating from its associated nozzle 144 is substantially the same. Aswill be appreciated, since the spools that are positioned mostdownstream have associated yarns extending through conduits 168 over asignificant distance, there is more friction and thus tension placed inthe yarns, than the yarns associated with spools at more upstreampositions. Accordingly, the compression or resistance set in the moredownstream yarns by the tensionsers would be less than for thetensioners associated with the upstream spools. By adjusting the tensionof the yarn of each spool, however, it will be seen that the tension inthe yarns emanating from the nozzles can be substantially equalized foruniform application to the warp yarns passing beneath the laydown ring.

Although the present invention has been described with a certain degreeof particularity, it is understood that the disclosure has been made byway of example, and changes in detail or structure may be made withoutdeparting from the spirit of the invention as defined in the appendedclaims.

1. An apparatus for wrapping weft yarns around a cylindricallyconfigured sheet of warp yarns comprising in combination: an elongatedtube rotatable about its longitudinal axis, said tube circumferentiallysurrounding said cylindrically configured sheet of warp yarns such thatsaid warp yarns can be moved linearly in a downstream direction throughsaid rotatable tube, means for moving said sheet of warp yarns linearlythrough said rotatable tube, a plurality of spools of weft yarn securedto said tube in circumferentially spaced relationship, guide systems forconfining and guiding said weft yarns in an upstream direction to anupstream location on said tube, and a laydown member at said upstreamlocation for receiving weft yarns from said spools and depositing theweft yarns on said warp sheet as said tube is rotated and said warpsheet is moved linearly past said upstream location.
 2. The apparatus ofclaim 1 wherein said laydown member has a sloped surface converging in adownstream direction onto which said weft yarns are wrapped prior tobeing deposited on said warp sheet from said sloped surface.
 3. Theapparatus of claim 1 further including a plurality of locations alongthe length of said tube having circumferentially spaced spools of weftyarn.
 4. The apparatus of claim 1 or 3 further including a yarntensioning system for creating substantially uniform tension in saidweft yarns before they are deposited onto said laydown member.
 5. Theapparatus of claim 1 or 2 wherein said laydown member is a non-rotatablering surrounding said cylindrically configured transfer belt and warpsheet.
 6. The apparatus of claim 5 wherein said laydown member islinearly movable along the length of said cylindrically configuredtransfer belt and warp sheet.
 7. The apparatus of claim 4 wherein saidtensioning system includes a generally cylindrical surface along whichsaid weft yearns can be engaged for frictionally inhibiting slidingmovement of the weft yarns to create uniform tension therein.
 8. Theapparatus of claim 7 further including adjustable means for selectivelyadjusting the length of the generally cylindrical surface along whichthe weft yarns are engaged.
 9. The apparatus of claim 8 wherein saidtensioning system is on said rotatable tube.
 10. The apparatus of claim4 wherein said tensioning system is an adjustable spring biased devicefor creating a selected tension in a weft yarn passing therethrough. 11.The apparatus of claim 10 wherein there is a tensioning deviceassociated with each spool of weft yarn.
 12. The apparatus of claim 10wherein said device includes a fixed plate and a movable plate, andwherein the movable plate is spring biased toward the fixed plate suchthat a weft yarn slidably positioned between said plates is yieldinglyresisted in movement.